Permutation in String

Given two strings `s1` and `s2`, return `true` if `s2` contains a permutation of `s1`, or `false` otherwise. In other words, return `true` if one of `s1`'s permutations is the substring of `s2`.   **Example 1:** **Input:** s1 = "ab", s2 = "eidbaooo" **Output:** true **Explanation:** s2 contains one permutation of s1 ("ba"). ``` **Example 2:** **Input:** s1 = "ab", s2 = "eidboaoo" **Output:** false ```   **Constraints:** - `1 <= s1.length, s2.length <= 104` - `s1` and `s2` consist of lowercase English letters.